import java.util.List;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: LIUYANJIAO
 * Date: 2024-10-25
 * Time: 13:59
 */
public class Main {
    public class TreeNode {
      int val;
      TreeNode left;
      TreeNode right;
      TreeNode() {}
      TreeNode(int val) { this.val = val; }
      TreeNode(int val, TreeNode left, TreeNode right) {
          this.val = val;
         this.left = left;
          this.right = right;
      }
    public List<List<Integer>> levelOrderBottom(TreeNode root) {

    }
    public static void main(String[] args) {


    }
}